Milt Bearden, the highly respected CIA operative who managed American covert operations to aid the Afghan mujahedin during the Soviet War, has strong cautions in an op-ed on a possible war with Iran in the International Herald Tribune. An excerpt:

"The Bush administration might dismiss the need to negotiate with Iran's blustering president, Mahmoud Ahmadinejad, over Tehran's nuclear aspirations and the proxy wars it is accused of waging in Iraq, Syria, Lebanon and Palestine. But Washington should nevertheless remember that the modern nation of Iran traces its roots back to ancient Persia and that beneath every Iranian lies a Persian who views his country in the context of "Greater Iran." Even before Rome conquered the Western world, the lands controlled by a series of Persian empires stretched from the Caucasus to the Indus River, a cultural and sometimes political arc that not so long ago contained Iraq and Afghanistan and much, much more."

It is almost certainly true that the Pasdaran is providing military aid to Shiite militias inside Iraq and possible to likely that Hezbollah operatives are present as well. Where this leads to deaths or injury of American troops, it is perfectly appropriate for U.S. forces to retaliate or even initiate lethal operations if that is what is required to "send a message" to indicate the kinds of conduct that will not be tolerated. Trying to root out Iranian personnel "fish" from the Iraqi Shiite population "sea" is a hopeless task for U.S. troops. Applying pressure to Iranian interests inside Iraq, or even across the Iranian border, on the other hand, is more easily done. At times, it can be stealthily done, depending on the message CENTCOM or Washington would care to send Teheran.

Moreover, there is no reason, to cite the Afghan War example, that we cannot bleed Iranian special operatives on Iraqi streets even as we talk to Iranian diplomatic plenipotentiaries across polished conference tables. We did it with the Soviets to good effect in the 1980's and the former activity seemed to reinforce the seriousness of the latter. The Iranian regime has many dangerous, hostile and fanatical elements but it is also riven with corruption, stultifying authoritarianism and looming economic problems. Teheran is not ten feet tall by any means nor is that factionalized, clerical, government as wholly irrational or erratic as is Pyongyang, to whom we do talk.

Diplomacy may fail but we shouldn't fail to try diplomacy before rolling the dice on a major war.

The Bearden article is very superficial; there is no analysis at all. Yes, I guess one option for Iran would be for the U.S. to do an "Iraq round two"; i.e. ground invasion followed by regime change and occupation. In this case his "analysis" is to point out that "invaders" have not done well in the past 100 years. Very deep analysis indeed. There are other military options available. Lastly, he repeats the "discussion at some point is inevitable," mime. They were going on for years through the Europeans to no avail...except to further the Iranian program.